1 /*- 2 * Parts Copyright (c) 1995 Terrence R. Lambert 3 * Copyright (c) 1995 Julian R. Elischer 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Terrence R. Lambert. 17 * 4. The name Terrence R. Lambert may not be used to endorse or promote 18 * products derived from this software without specific prior written 19 * permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY 22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD$ 34 */ 35 36 #include <sys/param.h> 37 #include <sys/kernel.h> 38 #include <sys/sysctl.h> 39 #include <sys/systm.h> 40 #include <sys/module.h> 41 #include <sys/malloc.h> 42 #include <sys/conf.h> 43 #include <sys/vnode.h> 44 #include <sys/queue.h> 45 #include <sys/ctype.h> 46 #include <machine/stdarg.h> 47 48 #define cdevsw_ALLOCSTART (NUMCDEVSW/2) 49 50 struct cdevsw *cdevsw[NUMCDEVSW]; 51 52 static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); 53 54 /* 55 * This is the number of hash-buckets. Experiements with 'real-life' 56 * udev_t's show that a prime halfway between two powers of two works 57 * best. 58 */ 59 #define DEVT_HASH 83 60 61 /* The number of dev_t's we can create before malloc(9) kick in. */ 62 #define DEVT_STASH 50 63 64 static struct specinfo devt_stash[DEVT_STASH]; 65 66 static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH]; 67 68 static LIST_HEAD(, specinfo) dev_free; 69 70 devfs_create_t *devfs_create_hook; 71 devfs_destroy_t *devfs_destroy_hook; 72 int devfs_present; 73 74 static int free_devt; 75 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 76 77 struct cdevsw * 78 devsw(dev_t dev) 79 { 80 if (dev->si_devsw) 81 return (dev->si_devsw); 82 return(cdevsw[major(dev)]); 83 } 84 85 /* 86 * Add a cdevsw entry 87 */ 88 89 int 90 cdevsw_add(struct cdevsw *newentry) 91 { 92 93 if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) { 94 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 95 newentry->d_name, newentry->d_maj); 96 return (EINVAL); 97 } 98 99 if (cdevsw[newentry->d_maj]) { 100 printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n", 101 newentry->d_name, cdevsw[newentry->d_maj]->d_name); 102 } 103 104 cdevsw[newentry->d_maj] = newentry; 105 106 return (0); 107 } 108 109 /* 110 * Remove a cdevsw entry 111 */ 112 113 int 114 cdevsw_remove(struct cdevsw *oldentry) 115 { 116 if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) { 117 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 118 oldentry->d_name, oldentry->d_maj); 119 return EINVAL; 120 } 121 122 cdevsw[oldentry->d_maj] = NULL; 123 124 return 0; 125 } 126 127 /* 128 * dev_t and u_dev_t primitives 129 */ 130 131 int 132 major(dev_t x) 133 { 134 if (x == NODEV) 135 return NOUDEV; 136 return((x->si_udev >> 8) & 0xff); 137 } 138 139 int 140 minor(dev_t x) 141 { 142 if (x == NODEV) 143 return NOUDEV; 144 return(x->si_udev & 0xffff00ff); 145 } 146 147 int 148 dev2unit(dev_t x) 149 { 150 int i; 151 152 if (x == NODEV) 153 return NOUDEV; 154 i = minor(x); 155 return ((i & 0xff) | (i >> 8)); 156 } 157 158 int 159 unit2minor(int unit) 160 { 161 162 KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit)); 163 return ((unit & 0xff) | ((unit << 8) & ~0xffff)); 164 } 165 166 static dev_t 167 allocdev(void) 168 { 169 static int stashed; 170 struct specinfo *si; 171 172 if (stashed >= DEVT_STASH) { 173 MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT, 174 M_USE_RESERVE | M_ZERO); 175 } else if (LIST_FIRST(&dev_free)) { 176 si = LIST_FIRST(&dev_free); 177 LIST_REMOVE(si, si_hash); 178 } else { 179 si = devt_stash + stashed++; 180 si->si_flags |= SI_STASHED; 181 } 182 LIST_INIT(&si->si_names); 183 TAILQ_INIT(&si->si_snapshots); 184 return (si); 185 } 186 187 dev_t 188 makedev(int x, int y) 189 { 190 struct specinfo *si; 191 udev_t udev; 192 int hash; 193 194 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 195 panic("makedev of NOUDEV"); 196 udev = (x << 8) | y; 197 hash = udev % DEVT_HASH; 198 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 199 if (si->si_udev == udev) 200 return (si); 201 } 202 si = allocdev(); 203 si->si_udev = udev; 204 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 205 return (si); 206 } 207 208 void 209 freedev(dev_t dev) 210 { 211 dev_t adev; 212 213 if (!free_devt) 214 return; 215 if (SLIST_FIRST(&dev->si_hlist)) 216 return; 217 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 218 return; 219 while (!LIST_EMPTY(&dev->si_names)) { 220 adev = LIST_FIRST(&dev->si_names); 221 adev->si_drv1 = NULL; 222 freedev(adev); 223 } 224 LIST_REMOVE(dev, si_hash); 225 if (dev->si_flags & SI_STASHED) { 226 bzero(dev, sizeof(*dev)); 227 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 228 } else { 229 FREE(dev, M_DEVT); 230 } 231 } 232 233 udev_t 234 dev2udev(dev_t x) 235 { 236 if (x == NODEV) 237 return NOUDEV; 238 return (x->si_udev); 239 } 240 241 dev_t 242 udev2dev(udev_t x, int b) 243 { 244 245 if (x == NOUDEV) 246 return (NODEV); 247 switch (b) { 248 case 0: 249 return makedev(umajor(x), uminor(x)); 250 case 1: 251 return (NODEV); 252 default: 253 Debugger("udev2dev(...,X)"); 254 return NODEV; 255 } 256 } 257 258 int 259 uminor(udev_t dev) 260 { 261 return(dev & 0xffff00ff); 262 } 263 264 int 265 umajor(udev_t dev) 266 { 267 return((dev & 0xff00) >> 8); 268 } 269 270 udev_t 271 makeudev(int x, int y) 272 { 273 return ((x << 8) | y); 274 } 275 276 dev_t 277 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...) 278 { 279 dev_t dev; 280 va_list ap; 281 int i; 282 283 KASSERT(umajor(makeudev(devsw->d_maj, minor)) == devsw->d_maj, 284 ("Invalid minor (%d) in make_dev", minor)); 285 286 dev = makedev(devsw->d_maj, minor); 287 if (dev->si_flags & SI_NAMED) { 288 printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n", 289 dev->si_name); 290 return (dev); 291 } 292 va_start(ap, fmt); 293 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 294 dev->si_name[i] = '\0'; 295 va_end(ap); 296 dev->si_devsw = devsw; 297 dev->si_uid = uid; 298 dev->si_gid = gid; 299 dev->si_mode = perms; 300 dev->si_flags |= SI_NAMED; 301 302 if (devfs_create_hook) 303 devfs_create_hook(dev); 304 return (dev); 305 } 306 307 dev_t 308 make_dev_alias(dev_t pdev, char *fmt, ...) 309 { 310 dev_t dev; 311 va_list ap; 312 int i; 313 314 dev = allocdev(); 315 dev->si_flags |= SI_ALIAS; 316 dev->si_flags |= SI_NAMED; 317 dev->si_drv1 = pdev; 318 LIST_INSERT_HEAD(&pdev->si_names, dev, si_hash); 319 320 va_start(ap, fmt); 321 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 322 dev->si_name[i] = '\0'; 323 va_end(ap); 324 325 if (devfs_create_hook) 326 devfs_create_hook(dev); 327 return (dev); 328 } 329 330 void 331 destroy_dev(dev_t dev) 332 { 333 334 if (!(dev->si_flags & SI_NAMED)) { 335 printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n", 336 major(dev), minor(dev)); 337 return; 338 } 339 340 if (devfs_destroy_hook) 341 devfs_destroy_hook(dev); 342 dev->si_drv1 = 0; 343 dev->si_drv2 = 0; 344 dev->si_devsw = 0; 345 dev->si_flags &= ~SI_NAMED; 346 dev->si_flags &= ~SI_ALIAS; 347 freedev(dev); 348 } 349 350 const char * 351 devtoname(dev_t dev) 352 { 353 char *p; 354 int mynor; 355 356 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 357 p = dev->si_name; 358 if (devsw(dev)) 359 sprintf(p, "#%s/", devsw(dev)->d_name); 360 else 361 sprintf(p, "#%d/", major(dev)); 362 p += strlen(p); 363 mynor = minor(dev); 364 if (mynor < 0 || mynor > 255) 365 sprintf(p, "%#x", (u_int)mynor); 366 else 367 sprintf(p, "%d", mynor); 368 } 369 return (dev->si_name); 370 } 371 372 int 373 dev_stdclone(char *name, char **namep, char *stem, int *unit) 374 { 375 int u, i; 376 377 i = strlen(stem); 378 if (bcmp(stem, name, i) != 0) 379 return (0); 380 if (!isdigit(name[i])) 381 return (0); 382 u = 0; 383 while (isdigit(name[i])) { 384 u *= 10; 385 u += name[i++] - '0'; 386 } 387 *unit = u; 388 if (namep) 389 *namep = &name[i]; 390 if (name[i]) 391 return (2); 392 return (1); 393 } 394 395 /* 396 * Helper sysctl for devname(3). We're given a {u}dev_t and return 397 * the name, if any, registered by the device driver. 398 */ 399 static int 400 sysctl_devname(SYSCTL_HANDLER_ARGS) 401 { 402 int error; 403 udev_t ud; 404 dev_t dev; 405 406 error = SYSCTL_IN(req, &ud, sizeof (ud)); 407 if (error) 408 return (error); 409 if (ud == NOUDEV) 410 return(EINVAL); 411 dev = makedev(umajor(ud), uminor(ud)); 412 if (dev->si_name[0] == '\0') 413 error = ENOENT; 414 else 415 error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1); 416 freedev(dev); 417 return (error); 418 } 419 420 SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY, 421 NULL, 0, sysctl_devname, "", "devname(3) handler"); 422 423